The prior art discloses that fibrous webs, made predominately of papermaking fibers, can be reinforced to make a laminated web structure suitable for use as a heavy duty wiper. This is generally accomplished by adhering a reinforcing layer to one or more plies of uniform density webs, such as tissue.
One prior art laminated structure using tissue layers is disclosed in U.S. Pat. No. 3,862,877--Camden comprising three layers of tissues and in which a large quantity of particular soft, tacky, nonmigratory binder solids is impregnated in a centrally located tissue which is faced with additional outer tissue layers.
U.S. Pat. No. 3,709,764--Thomas disclosed a laminated wiper in which one or more plies of cellulosic tissue layers are placed between outer scrim layers.
U.S. Pat. No. 3,953,638--Kemp discloses a laminated wiper structure which includes a relatively inextensible central ply of cellulosic tissue paper which is reinforced by imprinting an intermittent pattern of a suitable polymer resin on each surface. The outer plies of the wiper are highly extensible creped cellulosic tissue paper which are intermittently adhered to the surface of the reinforced central ply.
U.S. Pat. No. 3,879,257--Gentile et al, assigned to the assignee of this invention, discloses a single-ply fibrous web that has a laminate-like structure which consists of a soft, absorbent central core region of relatively low fiber concentration sandwiched between two strong, abrasion resistant surface regions of higher fiber concentration. The surface regions have bonding material therein to provide strength and the bonded areas in at least one of the surface regions is finely creped. The Gentile, et al. patent also discloses a method of making a laminate-like web from an already formed fibrous web, the method, including the steps of applying to one side of the web bonding material which penetrates from about 10 to about 60 percent through the thickness of the web, applying to the other side of the web bonding material in a fine spaced apart pattern which penetrates from about 10 to about 60 percent through the thickness of the web but which does not substantially connect with the first bonding material, adhering said other side of the web to a creping surface by means of the bonding material, and creping the web from the creping surface.
It is also known in the prior art to form a laminated web structure by laminating a stranded scrim in between two fibrous webs made in accordance with the above-mentioned Gentile, et al. patent. The spacing of the scrim strands results in apertures of about 0.079 square inches in the scrim. Applicants have found that these relatively large nonreinforced areas make the laminated structure unsuitable as a heavy duty wiper because the relatively large nonreinforced areas are susceptible to punctures and do not provide acceptable abrasion resistance over the entire surface of the wiper.
U.S. Pat. No. 2,834,809--Schutte et al. describes a method, known as perf-embossing, of mechanically working fibrous webs to make them more absorbent and conformable. In the method of Schutte et al., the web is passed through the nip of two rolls, the surface of each roll comprised of a plurality of projections and depressions so arranged that the projections of each roll mates with corresponding depressions in the other roll. As the fibrous web passes through the nip of the two rolls portions of the web are compressed while portions of the web between the compressed areas are stretched beyond the elastic limit of the fibers or interfiber bonds which causes the fibers to separate which increase the porosity of the web. In some cases the tensile strength of the paper is exceeded resulting in apertures being formed in the web. Schutte, et al recognize that multi-ply webs can be mechanically worked by their process.